This is my report from my degree project at SCS (Swedish Control System) in Åmål. It is made in co-operation with the department of Electrical Engineering at Karlstad University. For a long time SCS had worked with development of controller cards for lift equipment so-called QUICK-LIFT. They are manufactured by Kahlman Produkter AB in Vänersborg. Self-oscillation is a well-known problem when it comes to this kind of equipment. It arises between the operator-operating handle-jib-motor. During many years a digital filter has been used to put out this unwanted resonance. The parameters for the filter are based on current weight taken from a load cell. The resonance depends on the jib angle. In brief my task is to examine and measure up how the jib angle and load weight influence the mechanical resonance. The aim is to use the signal from the sensor and connect it to and existing controller card and if it is possible use it to put out resonance shown to be dependent on the jib angle.